using System;
using System.Collections.Generic;
using System.Text;

namespace _1BT01
{
    class Point
    {
            private double x;
            private double y;
            // Default Constructor
            public Point()
            {
                // Set the internal values
                this.x = 0;
                this.y = 0;
            }

            // Standard Constructor
            public Point(double X, double Y)
            {
                // Set the internal values
                this.x = X;
                this.y = Y;
            }
            public double ChieuDai(Point P1)
            {
                double l = Math.Sqrt(Math.Pow((P1.x - this.x), 2) + Math.Pow((P1.y - this.y), 2));
                return l ;
            }
    }
}
